title: Targeted next generation sequencing in SPAST-negative hereditary spastic paraplegia.
abstract: Molecular characterization is important for an accurate diagnosis in hereditary spastic paraplegia (HSP). Mutations in the gene SPAST (SPG4) are the most common cause of autosomal dominant forms. We performed targeted next generation sequencing (NGS) in a SPAST-negative HSP sample. Forty-four consecutive HSP patients were recruited from an adult neurogenetics clinic in Sydney, Australia. SPAST mutations were confirmed in 17 subjects, and therefore 27 SPAST-negative patients were entered into this study. Patients were screened according to mode of inheritance using a PCR-based library and NGS (Roche Junior 454 sequencing platform). The screening panel included ten autosomal dominant (AD) and nine autosomal recessive (AR) HSP-causing genes. A genetic cause for HSP was identified in 25.9 % (7/27) of patients, including 1/12 classified as AD and 6/15 as AR or sporadic inheritance. Several forms of HSP were identified, including one patient with SPG31, four with SPG7 (with one novel SPG7 mutation) and two with SPG5 (including two novel CYP7B1 frameshift mutations). Additional clinical features were noted, including optic atrophy and ataxia for patients with SPG5 and ataxia and a chronic progressive external ophthalmoplegia-like phenotype for SPG7. This protocol enabled the identification of a genetic cause in approximately 25 % of patients in whom one of the most common genetic forms of HSP (SPG4) was excluded. Targeted NGS may be a useful method to screen for mutations in multiple genes associated with HSP. More studies are warranted to determine the optimal approach to achieve a genetic diagnosis in this condition.
authors.affiliation: Department of Neurogenetics, Kolling Institute of Medical Research, Royal North Shore Hospital and The University of Sydney, Pacific Hwy, St Leonards, Sydney, NSW, 2065, Australia, kkum4618@uni.sydney.edu.au.
authors.forename: Kishore R
authors.initials: KR
authors.lastname: Kumar
authors.forename: Nicholas F
authors.initials: NF
authors.lastname: Blair
authors.forename: Himesha
authors.initials: H
authors.lastname: Vandebona
authors.forename: Christina
authors.initials: C
authors.lastname: Liang
authors.forename: Karl
authors.initials: K
authors.lastname: Ng
authors.forename: David M
authors.initials: DM
authors.lastname: Sharpe
authors.forename: Anne
authors.initials: A
authors.lastname: Grünewald
authors.forename: Uta
authors.initials: U
authors.lastname: Gölnitz
authors.forename: Viatcheslav
authors.initials: V
authors.lastname: Saviouk
authors.forename: Arndt
authors.initials: A
authors.lastname: Rolfs
authors.forename: Christine
authors.initials: C
authors.lastname: Klein
authors.forename: Carolyn M
authors.initials: CM
authors.lastname: Sue
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics*; D000293:Adolescent; D000328:Adult; D001315:Australia; D002648:Child; D002675:Child, Preschool; D005260:Female; D005838:Genotype; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D010641:Phenotype; D017422:Sequence Analysis, DNA; D015419:Spastic Paraplegia, Hereditary / Q000175:diagnosis* / Q000235:genetics*; D000074181:Spastin; D055815:Young Adult
chemical_list: D000251:Adenosine Triphosphatases; D000074181:Spastin; C400283:SPAST protein, human